An electrical engineer wants to compare the resistance of four types of wire made from different materials.Five wires of equal lengths and cross sectional areas are prepared for each of the four wire types.Each section of wire is randomly tested by sending a current through the wire and measuring the resistance.The box plots for the four wire types are shown below.
A)Yes,the widths of the boxes are all the same.
B)Yes,all the groups look like they are normally distributed.
C)No,the spreads of the four groups look different.The response may need to be re-expressed before proceeding with the ANOVA.
D)No,the centre lines are steadily increasing.
E)Yes,the spreads look similar enough to proceed with the ANOVA.

Question

An electrical engineer wants to compare the resistance of four types of wire made from different materials.Five wires of equal lengths and cross sectional areas are prepared for each of the four wire types.Each section of wire is randomly tested by sending a current through the wire and measuring the resistance.The box plots for the four wire types are shown below. 
A)Yes,the widths of the boxes are all the same. 
B)Yes,all the groups look like they are normally distributed. 
C)No,the spreads of the four groups look different.The response may need to be re-expressed before proceeding with the ANOVA. 
D)No,the centre lines are steadily increasing. 
E)Yes,the spreads look similar enough to proceed with the ANOVA.

Quizplus · Accepted Answer

The spreads of the four groups look different. This suggests that the variances of each group may not be equal, which violates the assumption of equal variances required for ANOVA. Therefore, the response may need to be re-expressed before proceeding with the ANOVA.

An Electrical Engineer Wants to Compare the Resistance of Four